I read this thread before spending several hours trying things and reading various threads, including a 64-page thread on another site which deals with ROMs and Emulation. I'm not an expert or anything, just a dad trying to get the thing working for the family.
In an attempt to save someone else the same wasted time in just getting the game to work at all, I'll post the conclusions I came to.
I'm not saying this is the best answer, just as far as I got in that time.
So:
1. Make sure you're running the Edge 1.5 OS.
2. Download the 27th October 2009
Cheats.dat file (and enable
cheats)
3. Use a clean, unpatched rom (the Xenophobia (U) rom)
4. Highlight the 'game fix' cheat when it loads and start.
This leaves the issue of game freezes mentioned above.
Seems we'll just have to put up with that for the time being.
Hope that helps for anyone in the same position I was.
(If I'd worked the same amount of time I spent messing about as overtime at work, I could have bought the damn game three times over!)